(CN) – Environmental advocacy groups filed a federal lawsuit Wednesday against the Interior Department, claiming that officials approved the expansion of a Montana coal mine without properly assessing the possible economic environmental clean-up costs of it.
In a long-standing dispute dating back to 2015 over the Bull Mountain mine north of Billings, Montana, the U.S. Office of Surface Mining was previously sued for approving expansion of mining operations on the site by Signal Peak Energy without conducting an adequate environmental assessment.
In August 2017, U.S. District Judge Donald Molloy agreed with the advocacy groups and issued an injunction blocking Signal Peak Energy from producing more coal from the site until the government completed a new environmental study. In November of that same year, he modified the injunction to allow the company to continue developing coal tunnels but not mine the coal.
The company makes use of an underground mining method known as “long-wall panels,” where tunnels running parallel are mined in sequence. The expansion would run under several parcels of land, opening up a 176-million-ton coal reserve.
According to the lawsuit filed Wednesday in federal court in Montana, the conservation groups, including 350 Montana and the Sierra Club, government officials again approved of the mining operation in August 2018 and “doubled down on their original errors” by failing to acknowledge the environmental costs.
“The agencies did so in the face of expert evidence that the harm from the mine expansion, from greenhouse gas pollution and toxic and harmful air pollution, would cost the public billions of dollars and be 5 to 15 times greater than the economic benefits of the mine,” the complaint states.
The groups said expansion of the mining site would cost the public billions of dollars from coal combustion pollution, spilt coal in state waters and “affect threatened and endangered species, including grizzly bear.”
Additionally, the conservation groups say the mining expansion could damage the region’s already scarce water supply used by local farmers.
“The long-wall mining method used by Signal Peak at the Bull Mountains Mine and proposed for the mine expansion results in subsidence or collapse of the land above the mine,” the lawsuit stated, adding that such collapses can affect streams and water springs.
Of the five springs undermined in the Bull Mountains, “four have shown diminished water levels and two of the four have actually gone dry,” the complaint says.
The lawsuit also makes note of the increase in trains the expansion would require to ship the coal overseas to countries like China, noting that the trains’ engines run on diesel fuel that will contribute to air pollution and may affect the health of local residents.
The complaint asks the court to halt the expansion and order the government to comply with environmental regulations.
The plaintiffs are represented by Shiloh Hernandez and Laura King of the Western Environmental Law Center in Helena.